US3764301A - Operation of a blast furnace - Google Patents

Operation of a blast furnace Download PDF

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Publication number
US3764301A
US3764301A US00093664A US3764301DA US3764301A US 3764301 A US3764301 A US 3764301A US 00093664 A US00093664 A US 00093664A US 3764301D A US3764301D A US 3764301DA US 3764301 A US3764301 A US 3764301A
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US
United States
Prior art keywords
furnace
zinc
coke
carbon
fuel
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Expired - Lifetime
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US00093664A
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English (en)
Inventor
S Morgan
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Metallurgical Processes Ltd
Imperial Smelting Corp Ltd
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Metallurgical Processes Ltd
Imperial Smelting Corp Ltd
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B19/00—Obtaining zinc or zinc oxide
    • C22B19/34—Obtaining zinc oxide
    • C22B19/36—Obtaining zinc oxide in blast or reverberatory furnaces

Definitions

  • 'I'his invention relates to the operation of a zinc, or zinc/lead, blast furnace.
  • molten reduced iron and the slag are removed from the bottom of the furnace and blast gases from the top.
  • a zinc blast furnace slag is removed from the bottom and vaporised zinc is included in the blast gases from the top of the furnace, from which gases the zinc may be recovered by absorption in a spray of molten lead droplets.
  • lead-zinc blast furnace normally used in practice, lead (and conceivably copper and other metals in minor amounts) is additionally removed from the bottom of the furnace as a molten lead bullion.
  • Carbon will react with carbon dioxide to form a carbon monoxide according to the equation If the temperature is below 1000 C., this CO will not reduce ZnO and hence can be termed useless CO. Moreover, the reaction is endothermic. Accordingly, any such reaction between carbon dioxide and hot carbon in the upper part of the furnace shaft tends to waste carbon both by virtue of the carbon lost and the consumption of additional carbon to compensate for the loss of heat in the endothermic reaction. It is therefore an economic penalty.
  • the present invention accordingly provides a method of operating a zinc or zinc/ lead blast furnace by feeding into the top of a furnace shaft oxidic materials and/ or oxidic zinc/lead materials together with a carbonaceous fuel and reducing agent, and at the bottom of said shaft a supply of blast air, wherein there is used as fuel a carbonaceous heat-producing and metallurgically reducing material in lump form, which has been subjected to a treatment to reduce its reactivity to carbon dioxide at 1000 C.
  • the fuel can be either a normal tired metallurgical coke, usually screened and graded, or a pre-formed briquetted material made from relatively small-sized carbonaceons material. Alternatively it can be partof a mixed briquette feed comprising carbon, oxidic metallurgeous material, slagging materials and binder.
  • the preferable fuel is one in which a physical barrier material has been provided, to prevent or hinder access of carbon dioxide to the carbon in the fuel Whilst in the upper part of the furnace.
  • This material can coat the whole lump of fuel; alternatively or additionally it can coat the walls of the pores or interstices within the lump of fuel.
  • Such a barrier ⁇ should disintegrate, melt or otherwise disappear in the lower part of the furnace.
  • such a physical or mechanical barrier can be an inorganic material inert to the smelting process; however, it is possible to provide a barrier of carbon of smaller pore size (or with no pores) which will not react appreciably until it reaches the lower part of the furnace.
  • lumps of fuel can be contacted (e.g. by dipping or spraying) with an aqueous solution or suspension of a suitable inorganic acid, base or salt which leaves a solid barrier residue on drying and/ or heating.
  • suitable inorganic acid e.g. boric acid, calcium oxide or hydroxide or carbonate, silicates such as sodium silicate or borates such as borax.
  • the lumps of fuel can be contacted with (e.g. dipped in or sprayed with) molten pitch or tar and preheated, before use in the furnace, to drive olf volatile materials and form a carbon seal.
  • the feed to the furnace is without a coating of non-carbonaceons materials, but due to the greatly reduced surface area, which converts the coke or briquettes from a porous sponge-like material to a substantially smooth material, the surface area available for the carbon/ carbon dioxide reaction is markedly reduced to a level suicient to make the material which otherwise is too reactive, useful in the furnace.
  • the normal preheating before the coke is charged to the furnace is utilized to drive off any water present and leave the inorganic material, or to drive olf volatile material from the pitch or tar.
  • Spraying of preheated coke can also be used, and when briquettes are used the solution or suspension can be sprayed on the hot briquettes for the same purpose. Since, however, pitch or tar does not lend itself to such a procedure it would be necessary to cool the briquettes after forming, coat them with pitch or tar, and re-heat before charge. This is expensive and accordingly the use of formed briquettes with pitch or tar is -not preferable. However, if formed briquettes are to be used it is possible to incorporate the inorganic materials referred to above (either as such or in aqueous solution or suspension) into the mixture from which the briquettes are to be made.
  • the reactivity of the material may be measured by a variety of standardized procedures; the one preferred is Patented Oct. 9, 1973 to determine the rate of loss of Weight of a crushed sample of coke or other carbon in a stream of pure carbon dioxide when heated to 1000 C. By this technique the rate of loss of weight of the coke can be determined.
  • a measurement under these conditions which gives a rate of weight loss in excess of 0.20 grams/sec. per cubic centimeter of carbon dioxide usually corresponds to a coke of unacceptably high reactivity when used in a zinc blast furnace. Usually less than 0.15 gm./ seo/cc. is preferred.
  • the ratio of CO to CO2 in the gas at the top of the charge can be used to indicate the amount of carbon being consumed by reaction with CO2.
  • the CO/COZ ratio would increase to 4.0. Under these latter conditions the net heat available for smelting (Le.
  • FIG. 1 is a graph of weight loss of treated fuel against weight loss of corresponding untreated fuel under specified heating conditions
  • FIG. 2 is a graph of CO/CO'Z ratio in a furnace trial comparing treated and untreated fuel.
  • EXAMPLE 1 This example illustrates the Weight loss of treated and untreated lump coke samples due to reaction with carbon dioxide at 1000 C.
  • the coke sample was heated at 1000 C. in a stream of carbon dioxide and the weight loss is expressed in terms of the percentages of the weight of sample lost per minute.
  • the treated coke was coated by spraying with a 2.5% solution of boric acid in water.
  • EXAMPLE 2 This shows the effect of using coke deactivated by treatment with boric acid solution as feed to a zinc/lead blast furnace. As will be observed from Table 2 and FIG. 2 certain furnace benefits accrue from the use of deactivated coke, more particularly a more constant CO/ CO2 ratio during the course of the campaign and improved slag hearth characteristics.
  • oxidic zinciferous material in lump form and carbonaceous material in lump form are fed to the top of the furnace an-d a supply of air is fed through tuyeres to the bottom of said furnace
  • the improvement comprising treating the carbonaceous material with an inorganic barrier material selected from carbon, boric acid, calcium oxide or hydroxide or carbonate, sodium silicate and borax before introduction of said carbonaceous material into the topA of the furnace so as to reduce the reactivity of said carbonaceous material to carbon dioxide at 1,000 C., whereby said treated carbonaceous material remains substantially unreactive to carbon dioxide as it descends said shaft, and combusts completely near the bottom of said furnace.
  • an inorganic barrier material selected from carbon, boric acid, calcium oxide or hydroxide or carbonate, sodium silicate and borax
  • a method as claimed in claim 7 wherein the organic barrier material is calcium carbonate.
  • a method as claimed in claim 7 wherein the organic barrier material is borax.
  • inorganic barrier material is carbon wherein any pores are of smaller pore size than those of the lump fuel material.
  • a method as claimed in claim 12 wherein prior to use in the furnace the lump fuel material has been contacted with molten pitch and subsequently heated to drive olf volatile material and leave a barrier carbon residue wherein any pores are of smaller pore size.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Solid Fuels And Fuel-Associated Substances (AREA)
US00093664A 1969-12-03 1970-11-30 Operation of a blast furnace Expired - Lifetime US3764301A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB5914169 1969-12-03

Publications (1)

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US3764301A true US3764301A (en) 1973-10-09

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US00093664A Expired - Lifetime US3764301A (en) 1969-12-03 1970-11-30 Operation of a blast furnace

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US (1) US3764301A (cs)
JP (1) JPS5133846B1 (cs)
AR (1) AR194189A1 (cs)
BE (1) BE759769A (cs)
BG (1) BG20122A3 (cs)
CA (1) CA925705A (cs)
CS (1) CS163231B2 (cs)
DE (1) DE2058942A1 (cs)
ES (1) ES386063A1 (cs)
FR (1) FR2072803A5 (cs)
GB (1) GB1301298A (cs)
HU (1) HU164939B (cs)
IE (1) IE34784B1 (cs)
IL (1) IL35718A0 (cs)
PL (1) PL81254B1 (cs)
RO (1) RO61892A (cs)
SU (1) SU388412A3 (cs)
TR (1) TR17326A (cs)
ZA (1) ZA708177B (cs)
ZM (1) ZM13770A1 (cs)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102533301A (zh) * 2012-01-13 2012-07-04 曹金贵 焦煤改质剂
CN114965848A (zh) * 2022-05-27 2022-08-30 福建三钢闽光股份有限公司 一种评价高炉用捣固焦反应性的方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4606760A (en) * 1985-05-03 1986-08-19 Huron Valley Steel Corp. Method and apparatus for simultaneously separating volatile and non-volatile metals

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102533301A (zh) * 2012-01-13 2012-07-04 曹金贵 焦煤改质剂
CN102533301B (zh) * 2012-01-13 2013-10-30 曹金贵 焦煤改质剂
CN114965848A (zh) * 2022-05-27 2022-08-30 福建三钢闽光股份有限公司 一种评价高炉用捣固焦反应性的方法

Also Published As

Publication number Publication date
JPS5133846B1 (cs) 1976-09-22
FR2072803A5 (cs) 1971-09-24
CA925705A (en) 1973-05-08
ZM13770A1 (en) 1971-07-22
CS163231B2 (cs) 1975-08-29
BE759769A (fr) 1971-05-17
GB1301298A (cs) 1972-12-29
RO61892A (cs) 1977-08-15
BG20122A3 (bg) 1975-10-30
SU388412A3 (cs) 1973-06-22
DE2058942A1 (de) 1971-07-01
IE34784L (en) 1971-06-03
ZA708177B (en) 1972-07-26
PL81254B1 (cs) 1975-08-30
HU164939B (cs) 1974-05-28
AR194189A1 (es) 1973-06-29
TR17326A (tr) 1975-03-24
IE34784B1 (en) 1975-08-20
IL35718A0 (en) 1971-01-28
ES386063A1 (es) 1973-03-16

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